1. Field of the Invention
The present invention relates to a gate arm for retrofitting onto an existing cantilever crossing structure that does not have a traffic control arm associated with it.
2. Description of the Related Art
Railroad crossings, i.e. where railroad tracks and vehicular roadways cross each other, present a unique threat to vehicles when the crossings are not properly marked. Gate arms that lower in front of vehicles when a train is approaching greatly decrease the chance of collisions between vehicles and trains at these crossings. Yet, many of these crossings currently only have cantilever crossing structures with flashing red lights and are not provided with gate arms that can be deployed in front of vehicles to prevent them from entering the crossing when a train is approaching the crossing. For safety reasons, it is desirable to have gate arms at all such crossings. Currently, the only way to achieve this is to add separate gate arms with new foundations, masts, electrical wiring and controls to supplement the existing cantilevers. These traffic control devices can be extremely expensive.
It would be much more economical to retrofit existing cantilever crossing structures that do not currently have a traffic control arm associated with them with a retractable gate arm. In order for an existing cantilever crossing structure to be retrofitted with a gate arm, the arm must be installed on the existing structure. Also, when the gate arm is in its downward position, i.e. when the traffic is stopped by the gate arm, the arm must be at the correct height above the ground to meet existing traffic control requirements for such traffic control gate arms. Another consideration is that the gate arm must, when in its raised position, i.e. when the traffic is not being stopped by the gate arm, be out of the path of the traffic so that required roadway height and width clearances are maintained.
The present invention addresses all of these needs by providing a cantilever gate arm that can be inexpensively retrofitted to an existing cantilever crossing structure. Further, the present invention provides a gate that can be deployed downward to a position that is the proper height to control vehicular traffic and can, alternately, be raised to a position that maintains the necessary roadway height and width clearances when the gate is not in use.